I have a silly problem, it occurred somehow in the process of switching to fullscreen mode and back.
Is there a way to move tvpaint around so I can position it so that all of the interface is visible again?

To fix this, click with the left mouse button on one of the corner of the window and maintain it (like if you want to resize it) then, press the button Alt and don't release it.
Then drag your mouse. The window should normally schrink and the title bar will appear so you will be able to move it.

To fix this, click with the left mouse button on one of the corner of the window and maintain it (like if you want to resize it) then, press the button Alt and don't release it.
Then drag your mouse. The window should normally schrink and the title bar will appear so you will be able to move it.